Sublethal effects of growth-regulating insecticides of synthetic and botanical origins on the biological parameters of Spodoptera frugiperda (Lepidoptera: Noctuidae)

The objective of this study was to evaluate the effects of growth-regulating insecticides of synthetic (e.g., Certero 480 SC, Intrepid 240 SC, Match EC and Mimic 240 SC) and botanical origins (e.g., Azamax 1.2 EC, Agroneem 850 EC, Azact 2.4 EC and Fitoneem 850 EC) on the biological parameters and fertility life table of Spodoptera frugiperda (J.E. Smith) under laboratory conditions. Larvae were fed insecticides that were incorporated into artificial diets. To develop the fertility life table, the following biological parameters were evaluated: survival at 7 days after infestation (d.a.i) and survivorship at adult eclosion, duration of the neonate-to-adult eclosion period, larval and pupal weights and total fecundity (number of total eggs per female). The results indicated that S. frugiperda neonates surviving LC25 or LC50 concentrations of the evaluated insecticides showed longer larval and egg-to-adult periods, lower larval and pupal weights and reduced fecundity, when compared to the control treatment. Larvae exposed to Azamax at LC25 or LC50 concentrations showed the greatest increase in generation duration (75 d). In addition, S. frugiperda adults emerged from pupae when larvae reared on an artificial diet containing growth regulating insecticides of synthetic and botanical origins produced fewer females per female per generation (Ro). As well as, lower rates of natural population increase per day (rm) compared to insects fed the control diet. Our findings indicated that, neem-derived products and growth-regulating insecticides of synthetic origin may be employed within integrated management strategies that aim to keep populations of S. frugiperda below levels that cause economic damage. Similarly, they offer alternatives for insecticide resistance management programs.